In a method of manufacturing a tube of quartz glass by molding a hollow cylinder having a wall thickness of at least 20 mm, the cylinder is continuously fed under rotation about a rotational axis into a heating zone at a relative feed rate V.sub.C, softened and radially expanded under the effect of a gas pressure. A tube strand is continuously formed and is withdrawn at a withdrawal rate V.sub.T. In order to mold thick-walled initial hollow cylinders of quartz glass into tubes with larger diameter, the gas pressure is used as an actuating variable of a diameter regulation for the tube outer diameter or for a geometrical correlated parameter thereof, and in a pressure build-up phase the gas pressure is gradually increased from a lower initial value to a higher final value, and that the following applies to the ratio of V.sub.C and V.sub.T:V.sub.T=V.sub.C±0.2.Math.V.sub.C.

Methods and apparatus provide for an ultra-thin glass sheet having a thickness of less than about 0.3 mm, being of a non-developable 3D shape, and including at least one bend having a radius of curvature of less than about 200 mm.

A method of forming a part includes forming a glass-ceramic matrix composite material to form a pre-consolidated feedstock sheet with a pre-determined shape. The pre-consolidated feedstock sheet is sectioned into a first piece of pre-consolidated feedstock sheet and a second piece of pre-consolidated feedstock sheet. The first piece of pre-consolidated feedstock sheet and a second piece of pre-consolidated feedstock sheet are assembled with a second piece of pre-consolidated feedstock sheet to form a composite layup. The first piece of pre-consolidated feedstock sheet and the second piece of pre-consolidated feedstock sheet are joined by compressing the composite layup to form a glass-ceramic matrix composite part.

Methods and mold designs provide for fiducials in molding glass optical elements, such as glass lenses. A mold for use in the fabrication of a lens can include a first part of the mold including a first molding surface corresponding to a first surface of said lens, and a second part of the mold including a second molding surface corresponding to a second surface of said lens, the first and second part of the mold configured to apply pressure to a moldable material in at least one cavity therebetween, at least one marking structure located on at least one of the first part of the mold, the second part of the mold, or both, the at least one marking structure configured to form at least one fiducial in the molded structure. Such techniques are applicable to precision glass molding.

A mold for producing a barbed glass plate and a method for producing the barbed glass plate are disclosed. The barbed glass plate includes a body portion, a transition portion, and an extension portion. The body portion, the transition portion, and the extension portion cooperatively define a receiving space. The extension portion includes an external surface facing away from the receiving space. The mold includes a lower die and an upper die. The lower die includes a bottom wall and a side wall. The upper die includes a protrusion. When the upper die is engaged with the lower die, the protrusion protrudes into the cavity and is spaced apart from the side wall.

In a method of manufacturing a tube of quartz glass by molding a hollow cylinder having a wall thickness of at least 20 mm, the cylinder is continuously fed under rotation about a rotational axis into a heating zone at a relative feed rate V.sub.C, softened and radially expanded under the effect of a gas pressure. A tube strand is continuously formed and is withdrawn at a withdrawal rate V.sub.T. In order to mold thick-walled initial hollow cylinders of quartz glass into tubes with larger diameter, the gas pressure is used as an actuating variable of a diameter regulation for the tube outer diameter or for a geometrical correlated parameter thereof, and in a pressure build-up phase the gas pressure is gradually increased from a lower initial value to a higher final value, and that the following applies to the ratio of V.sub.C and V.sub.T:V.sub.T=V.sub.C0.2.Math.V.sub.C.

A window member includes a main part including a first side extending in a first direction, a second side extending in a second direction, and a first corner side connecting the first and second sides. The window member further includes a first side part in contact with the first side, a second side part in contact with the second side, and a first corner part connecting the first and second side parts. The first corner part includes a first upper corner part, a first middle corner part, and a first lower corner part. A lower surface of the first middle corner part has a first radius of curvature, a lower surface of the first lower corner part has a second radius of curvature, and the first radius of curvature is greater than the second radius of curvature.

A method of forming a part includes forming a glass-ceramic matrix composite material to form a pre-consolidated feedstock sheet with a pre-determined shape. The pre-consolidated feedstock sheet is sectioned into a first piece of pre-consolidated feedstock sheet and a second piece of pre-consolidated feedstock sheet. The first piece of pre-consolidated feedstock sheet and a second piece of pre-consolidated feedstock sheet are assembled with a second piece of pre-consolidated feedstock sheet to form a composite layup. The first piece of pre-consolidated feedstock sheet and the second piece of pre-consolidated feedstock sheet are joined by compressing the composite layup to form a glass-ceramic matrix composite part.

An apparatus for forming 3D glass for a smart phone, including a lower mold set including a first lower mold 52A and a first upper mold 50A having a cavity in which curved glass is formed between the first lower mold and the first upper mold when the first lower mold and the first upper mold are coupled, an upper mold set including a second lower mold 52B and a second upper mold 50B having a cavity in which curved glass is formed between the second lower mold and the second upper mold when the second lower mold and the second upper mold are coupled, and a plurality of support pins 60 supporting the upper mold set in the state in which the upper mold set has been spaced apart from the lower mold set at a specific interval.

An apparatus for forming 3D glass for a smart phone, including a lower mold set including a first lower mold 52A and a first upper mold 50A having a cavity in which curved glass is formed between the first lower mold and the first upper mold when the first lower mold and the first upper mold are coupled, an upper mold set including a second lower mold 52B and a second upper mold 50B having a cavity in which curved glass is formed between the second lower mold and the second upper mold when the second lower mold and the second upper mold are coupled, and a plurality of support pins 60 supporting the upper mold set in the state in which the upper mold set has been spaced apart from the lower mold set at a specific interval.